Precipitation

(1)Except as provided in Sentence (2), where a building component or assembly is exposed to precipitation, the component or assembly shall

• (a) minimize ingress of precipitation into the component or assembly, and
• (b) prevent ingress of precipitation into interior space.

(2)Protection from ingress of precipitation is not required where it can be shown that such ingress will not adversely affect any of

• (a) the health or safety of building users,
• (b) the intended use of the building, or
• (c) the operation of building services.

(1)Where protective materials are applied to assemblies to provide the required protection from precipitation, they shall be installed so as to shed precipitation or otherwise minimize its entry into the assembly and prevent its penetration through the assembly.

(2)Where protective materials described in Sentence (1) are part of a vegetative roofing system, they shall be resistant to root and rhizome penetration when tested in accordance with ANSI/GRHC/SPRI VR-1, "Procedure for Investigating Resistance to Root or Rhizome Penetration on Vegetative Roofs."

(1)Except as provided in Sentence (2), materials, components, assemblies, joints in materials, junctions between components and junctions between assemblies exposed to precipitation shall be

• (a) sealed to prevent ingress of precipitation, or
• (b) drained to direct precipitation to the exterior.

(2)Sealing or drainage are not required where it can be shown that the omission of sealing and drainage will not adversely affect any of,

• (a) the health or safety of building users,
• (b) the intended use of the building, or
• (c) the operation of building services.

(1)Where water, snow or ice can accumulate on a building, provision shall be made to minimize the likelihood of hazardous conditions arising from such accumulation.

(2)Where precipitation can accumulate on sloped or horizontal assemblies, provision shall be made for drainage conforming with Section 7.4.

(3)Where downspouts are provided and are not connected to a sewer, provisions shall be made to,

• (a) divert the water from the building, and
• (b) prevent soil erosion.

(4)Junctions between vertical assemblies, and sloped or horizontal assemblies, shall be designed and constructed to minimize the flow of water from the sloped or horizontal assembly onto the vertical assembly.

(1)A solar collector system is permitted to be installed above roofing materials conforming to Table 5.9.1.1.